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N0. 6l5,458; Patented Dec. 6, I898.

J. A. MILLER. I

STEAM GENERATOR.

(Appliation filed Apr 10, 1897.) (No Model.) 3 sheets sheet l.

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No. 6l5,458. Patented Dec/6, I898.

J. A; MILLER.

STEAM GENERATOR.

(Application filed Apr. 1.0, 1897.)

3 Sheets-Sheet 2.

(No Model.)

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WZTNIEEZE m: Noam: PETERS co Pua-rc-umou WASNINOTON. u. c.

No. 6l5,458. Patented nee. 6, I898.

J. A. MILLER.

STEAM GENERATOR.

(Application filed Apr. 10, 1897.) (No Model.) 3 Sheets- Sheet 3.

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UNITED- STATES PATENT OFFICE,

JOSEPH A. MILLER, or PROVIDENCE, RHODE ISLAND.

STEAM-GENERATOR.

SPECIFICATION forming part of Letters Patent No. 615,458, dated December6, 1898.

Application filed April 10, 1897.

To all whom it may concern.-

Be it known that I, JOSEPH A. MILLER,"of Providence, in the county ofProvidence and State of Rhode Island, have invented a new and usefulImprovement in Steam-Generators; and I hereby declare that the followingis a full, clear, and exact description of the same, reference being hadto the accompanying drawings, forming part of this specification.

This invention has reference to improvements in water-tubes such as areformed of a series of units or sections, each of which is connected withthe feed'water supply and the steam-main.

Tubulous or water-tube boilers, and particularly such as are to be usedfor marine purposes on board of steamers, should combine the highestpossible steam-generating capacity with the least possible weight in thesmallest possible space. The room for steamboilers on board of a ship isnecessarily limited, and every ton of weight saved increases the freightcapacity of the steamer. As heretofore constructed the fittingsconnecting the water-tubes exceeded in weight the weight of thesteanrgenerating tubes and a very large number of joints more or lessrigid and subject to the strain of the expansion and contraction of thetubes were used. In some types the tubes were expanded into the steamand water chambers, and these had to be made of large diameter, so as topermit the entrance of a person to expand the tubes. Another defect inWater-tube boilers as heretofore constructed is -found in theconnections between the water-tubes and between the discharging ends ofthe water-tubes and cases, boxes, or fittings into which the steam andwater are discharged, for when the ends of such tubes open into achamber the steam and water are discharged together and means have to beprovided forseparating the steam from the water. Such open ends permit afree discharge equal to the capacity of the tubes, and when the boileris forced the rapid generation of the steam forces the water out of thetubes, and the tubes are liable to be burned.

'The main difficulties with water-tube boilers have been inaccessibilityof the connecting-joints, the difficulty of inspecting and Serial No.631,543. (No model.)

cleaning the exterior and interior of the steam-generating surfaces, andthe diiiiculty of making repairs.

One object of the invention is to construct a water-tube boiler so thatall the steam-generating surfaces shall be formed of sheet metal and allthe joints made by expanding the tubes, thus combining the greatestavailable area of heating-surface and strength to withstand internalpressure with the least possible weight of the boiler when filled withwater in actual use.

Another object of the invention is to secure a large heating-surfaceextending over the fire at or nearly at right angles to the draft of thefire by the use of fewer tubes and fewer connections or joints thanheretofore used.

A further object of the invention is to so construct a water-tube boilerthat the joints or connections of the tubes shall not be subjected tostrains by the expansion or contraction of the tubes.

Another object of the invention is to construct a water-tube boiler sothat the units or parts to which the tubes are connected may be lightand comparatively small and all the tubes may be readily expanded andsecured from the exterior of the connectingchambers.

Another object of the invention is to construct the ends of thewater-tubes so that the discharge of the steam and water is limited andthe steam and water separately discharged into the connecting chamber orfitting.

Still another object of the invention is to so construct a water-tubeboiler that every joint or connection of the steam-generating tubes maybe readily examined and reached while in position and, if desired, whenthe boiler is in use.

A further object of this invention is to so construct a Water-tubeboiler that the main heatingsurface or the water and steam tubes may bereadily reached for cleaning and inspection.

Another object of the invention is to so'construct a water-tube boilerthat the interior of the steam-generating surfaces may be readilycleaned and inspected, and. a further object of the invention is toconstruct a water-tube boiler so that any one of the unitsmay be quicklyremoved and duplicate units inserted without enteringthe boiler andtherefore without waiting to cool the same.

The invention consists in the peculiar and novel construction of theunits or sections of which the boiler is made up and the combination ofthe parts by which the objects of the invention are secured, as will bemore fully set forth hereinafter.

' Figure 1 is a vertical sectional view of the water-tube boiler,showing one of the units or sections partly in section. Fig. 2 is afront view of the boiler, showing the main portion of the frontsupported on hinges arranged to open the front, so as to give access tothe boiler proper and permit of the removal or insertion of any one ofthe units or sections. Fig. 3 is a horizontal sectional view of thefront end of the boiler, showing the construction of the front doors.Fig. 4: is a side view, partly in section, of one of the sections orunits of the boiler; and Fig. 5, a rear view of the section. Fig. 6 is atransverse sectional 7 view of the unit-chamber, showing the ends of thesteam-generating water-tubes expanded into both of the flattened sidesof the unitchamber and the slits in the tubes connecting the interior ofthe tube with the interior ofthe unit-chamber. Fig. 7 is a transversesection of one of the tube ends, showing the slits, on an enlargedscale. Fig. 8 is a sectional View of the upper end of one of theunit-chambers,showing the steam-separating tube, the inlet-openings forthe steam, and the water-trip protected by a deflector. Fig. 9 is atransverse sectional view of two upper steam-generatingtubes of twoadjacent unitchambers, showing a plate resting on the two tubes forclosing the draft-opening between these tubes.

Similar letters of reference indicate corresponding parts in all thefigures.

In the drawings,A indicates the water-main, from which the water issupplied to the boiler. It is provided with the usual connections to thepump and the blow-off, and these connections are supplied with the usualvalves. They are not shown in the drawings, as they form no part of thepresentinvention.

B is the section or unit chamber. It is preferably made from a steeltube having the required diameter and length by fiatten-' ing the tubeinto the form shown in section in Fig. 6 of practically rectangularsection having two fiat sides B of greater width than the twoslightly-cu rved sides B The endsof the unit-chambers B are closed,preferably, by welding a piece into the ends.

0 O are the steam-generatin g tubes. They are bent so as to form loops,and the ends of these tubes extend through the fiat sides of theunit-chambers B, being secured by expanding the tubes. The ends of thetubes are closed by means of a plug or cap.

D indicates a steam-separator tube, preferably of larger diameter thanthe tubes 0 O. The tube D is secured at one end in the unitchamber B,above the tubes 0 0, preferably by expanding the tube D into theunit-chamber 13 and closing the end. The opposite end of the tube D isalso closed, and near the end it is connected with the steam-chamber E.

The steam-chamber E is provided with the usual steam connections andfittings, which, as they form no part of this invention, are not shownin the drawings.

F indicates the ash-pit; G, the grate; H, the furnace or combinationchamber; I, the firing-doors; K K, the two parts of the front supportedon hinges, so that the front may be readily opened; L, a beam extendingacross the front and forming part of the framing of the casing of theboiler; M, the up take, and N the smoke-flue.

0 indicates a suitable foundation for the boiler; P P, the support forthe unit-chamber B, and Q the tile or fire-brick lining of the furnace.I

The lower part of each unit-chamber B is connected with the water-main Aby pipes in which a union-coupling A is placed, so that any one of theunit-chambers may be readily disconnected. r j

The ends of the tubes 0 C are secured in holes bored into the fiat sidesof the'unitchambers by expanding the tubes. The portion of the tubeswithin the chamber are provided on the upper side with the long narrowslit 0' and near the bottom with the two slits C in place of the twoslits E One slit may be made into the bottom portion of the tubes,preferably of an area equal to the two slits C 0 These slits radiallydischarge the steam and water rushing through the upper ends of the benttubes 0 O and favor the separation of thesteam from the water. Theaggregate area'of the slitsis less than the area of the tube, and theoutflow of the water is retarded when the boiler is forced andfacilitates the escape of the steam, which always struggles to escapeupward and passes through the upper slit 0. The inclined positions ofthe water-tubes O O and the bends C facilitate the separation of thesteam from the water within the tubes, thereby preventing theaccumulation of steam in the tubes, particularly in the lower portionsof the tubes ex posed to the direct heatof the fire. The plate 0 isplaced between the two adjacent upper steam-generating tubes 0 O ofadjoining sections, so as to compel the gases to pass among and betweenthe other tubes and retard the escape'of the gases.

In the preferred form of construction shown in the drawings thesteam-separator tube D is provided with two inlet-openings d d at theupper part of the portion of the tube D ex-- dition the tube D is partlyfilled with water" the steam and water from the steam-generating tubes 0C will be deflectedin its up ward passage, and the steam, carrying somewater with it, will enter the tube D by the upper openings d d, as isindicated by the'arrows in Fig. 8. While the water in thesteam-generating tubes 0 C and unit-chamber B is in constant and rapidcirculation, the water in the tube D is comparatively quiet and presentsa large surface from which the steam made in the tube can readily escapeand pass into the steam-collecting chamber E.

The steam-chamber E is firmly supported on the brackets l, secured tothe beam L or some other firm and rigid support, and theconnecting-pipes 6, having the union 6, form sufficient supports for theends of the tubes D. These tubes may, however, be suitable straps, suchas L. (Shown in Fig. 1.)

While each unit, consisting of the tube D, the unit-chamber B, and thebent tubes 0 O, is sufficiently rigid when in use, it may bestrengthened by the strap D, (shown in Fig. 1,) consisting of a bentiron strap extending around the tube D, the ends of which are bolted toa vertical bar extending from near the tubes 0 C to near the tube D, anda similar strap inclosing the upper parts of the tubes 0 C and havingends bolted to the vertical bar to which the upper strap is bolted, orsome other similar stay may be used to facilitate the handling andtransportation of the units.

otherwise.

The ends of the steam-generating tubes C 0 when they have been securedinto the walls of the unit-chamber B by expanding the tubes with atube-expander are closed, preferably, by expanding wit-h a suitableexpander the cup-shaped caps G into the tubes. This firmly secures thecaps and holds the same against allpractical internal pressure. Byextending the tubular portions of the caps beyond the ends of the tubesC a simple tool may be used to crimp the cylindrical portion of the cap0 thereby contracting the diameter of the same and permitting theremoval of the caps and their reuse. I do not wish to confine myself tothe use of this form of caps, as the ends of the tubes 0 may be closedby screw-plugs'or other means.

For the purpose of cleaning or inspection the hand-holes C are placed inthe parts of the unit-chamber B shown in the drawings or other parts andclosed in the usual manner.

Any flat portion of the unit-chamber Bnot stayed by the tubes 0 may bestayed by means of the stay-tubes 0, consisting of short tubes closed atthe ends extending into the furnace and open at the opposite ends. Thesetubes are provided with the slits 0 0 They are securedin theunit-chamber, exactly as are the ends of the tubes 0, by expanding thetubes with an expander, and the open sides are afterward closed by thecaps or Bent tubes may, however, be used, as indicated in broken linesin Fig. 1, and located so as to properly stay all parts of the fiatsurfaces of the unit-chamber B.

The casing inclosing the boiler may be of sheet metal lined with tile,fire-brick, or asbestos. For marine purposes it must be strongly framed,so as to firmly support all parts under the varying conditions existingon board a ship. The corner-standards R are ,to the furnace and thewhole of the steamgenerating surface of the boiler for inspection,cleaning, or repairs, 7 \Vhen a unit or section is disconnected, abarrow, such as'is indicated in broken lines in Fig. 1, may be rolled inon the grate and a section drawn out and in the same mannera sectionquickly inserted. The fire-doors I form part of the doors K, while theash-pit doors F F form part of the fixed lower casing F Suitable bolts,such as the bolts K, are provided to firmly secure the doors K when theboiler is in use. 7

The units or sections which form the steamgenerating part of the boilerare formed entirely of sheet metal. They are for equal area ofheating-surface and capacity to withstand internal pressure of lessweight than water-tube boilers as heretofore constructed. All the jointsare made by expanding the tubes into the tube-sheets, preferably by aroller-expander, such as is now used to expand boiler-tubes into thetube-sheets. The tubes are all free toexpand and contract withoutexerting any strain on their fastenings due to such expansion orcontraction.

WVhen repairs are required, the doors K K are opened, the fire is drawn,the section requiring repair is disconnected from the steam and waterchambers, and the section maybe drawn out without waiting for the boilerto cool, another section may be inserted and connected, and the firesstarted. The repairs are made while the section is outside, and no onehas to enter the boiler or crawl into any contracted spaces to tighten ajoint or make any repairs. In cleaning the boiler by Opening the doors KK all the steam-generating surface may be sweptor cleaned by a broom orscraper.

Having thus described my invention, I claim as new and desire to secureby Letters Patent-- l. A water-tube boiler made up of a series of unitsor sections, having each a vertical unit-chamber, a series of bent tubesforming a continuous practically U-shaped loop both the ends of whichextend through the unitchamber and are secured in both sides of thesame, and connections between each unit- -chamber and the water andsteam mains,

whereby joints and fittings are avoided and the heating-surface exposedto the fire is formed of tubes both ends of which are secured to thesame vertical chamber, as dc scribed.

2. In a water-tube boiler, the combination with the furnace, the uptakeand the inclosing casing, of a series of units or sections eachconsisting of a vertical unit-chamber, a series of bent tubes forming acontinuous loop both ends of which extend through the unit-chamber andare secured to the two sides of the same by expanding the tubes, a tubesecured in the unit-chamber above the bent tubes and connections betweenthewater and steam mains and each section or unit, whereby the steamgenerated in the bent tubes is separated from the water, as described.

3. In a water-tube boiler, in combination, the furnace with its grate,fire-door and ashpit, a unit-chamber of practically rectangularcross-section supported in the rear of the furnace, its lower partconnected with the water-supply, a series of bent tubes forming acontinuous loop the ends of which extend through and are secured to bothsides of the same unit-chamber, said bent tubes extending from theunit-chamber over the furnace, connections between the steam-main andthe upper part of the unit-chamber and a casing inclosing the boiler thefront of which is constructed so as to be opened, whereby thesteam-generating tubes of each section or unit are free to expand andcontract and convenient access may be had to the steam-generatingsurface for cleaning and inspection, as described.

4. In a water-tube boiler, the combination with a series of sections orunits each consisting of a vertical chamber from which extend a seriesof bent tubes forming continuous loops the ends of which are secured tothe vertical chamber, the furnace, the grate and ash-pit, of a casinginclosing the boiler, the front of which casing, from the dead-plateupward to the top of the sections, is pivotally supported and adapted tobe swung open, whereby any one of the units or sections may be removedand the steam-generating surface conveniently cleaned, as described.

5. In a water-tube boiler, the combination with the series of units orsections consistmg each of a vertical unit-chamber, a series of benttubes forming acontinuous loop both ends of each bent tube secured inthe unitparts of the steam-generatin g surface between the grate and theuptake for cleaning, inspection and repairs, as described.

6. In a water-tube boiler composed of a series of sections or units, thecombination with the unit-chamber B having the flat sides B, B, of thebent tubes C, O, forming a continuous loop the two ends of each benttube being secured in both of the flat sides B, B of the unit-chamber,openings in the sides of the tubes connecting the interior of the tubeswith the interior of the unit-chamber, the caps 0 consisting of a tubeclosed at the inner end and secured by expanding the openend tubularportion into the open end of the tubes, by which the ends of the tubesare closed, and connections between the steam and Water mains and theunitchamber, whereby the tubes forming the steam-generating surfaceextending. from the rear to the front of the boiler over the fire arefree to expand and contract and the joints are protected against thedirect action of the fire.

7. In a water-tube boiler composed of a series of sections or units, thecombination with the unit-chamber B and the series of bent tubes 0, O,of the tube D, the inlet-openings d, d at the upper part of the tube,the opening 11 at the lower part of the tube and the deflector d wherebythe separation of the steam from the water is facilitated, as described.

8.- In a water-tube boiler, in combination, a series of sections orunits, each consisting of a unit-chamber of practically rectangularcross-section and extending vertically from a suitable support in therear of the furnace, a series of bent tubes extending from theunitchamber forward over the fire, the ends of said tubes being expandedinto two of the flat sides of the unit-chamber and the extreme endsclosed, a. steam-separating tube secured in the upper part of theunit-chamber above the bent tubes, connection with the steam and watermains, a casing inclosing the boiler, thefront of which is formed of ahinged door or doors, whereby when repairs are required a section may bequickly removed and another section inserted without entering theboiler, as described.

In witness whereof I have hereunto set my hand.

JOSEPH A. MILLER.

Witnesses:

J OSEPH A. MILLER, J r., M. F. BLIGH.

